1. Field of the Invention
This invention relates to a device that provides controlled release of a fragrant or deodorizing substance: the fragrant or deodorizing substance being solubilized in a carrier solvent within a polymeric matrix. The device can be mounted in almost any location but it is primarily intended for use inside an automobile by hanging from a rearview mirror or adhering to a window or another substantially flat surface. The device can be transparent so as to be inconspicuous or to permit viewing of an image bearing layer or may be colored by methods known to those skilled in the art.
2. Problems in the Art
Modification of the odor of the surrounding air has long been accomplished through the use of fragrant materials or deodorizing agents to mask and even neutralize offending odors. Malodor has been shown to cause nausea, headaches, coughing, irritation of mucous membranes, and shortness of breath. The need for odor modification is greatest in locations with an increased likelihood of offending odors, such as restrooms and kitchens, and in confined locations where people spend a considerable amount of time, such as an office or in an automobile.
Numerous methods to combat malodor in automobiles are documented in the patent literature. U.S. Pat. No. 4,814,212, Automobile Air Freshener Unit, by Spector (Mar. 21, 1989), describes adhesively attaching a framed replaceable gel air freshener to a car window. However, the Spector invention fails to provide any control over the rate of release and the device not a multi-laminate multi-layer device which possesses the advantages of such a system. Similar devices may be hung from rear view mirrors and can employ paper or cardboard substrates as fragrance reservoirs. Product use recommendations for such air fresheners provide an impractical procedure involving the gradual removal of the protective barrier film in order to manually regulate the rate of fragrance release over the period of use.
Air fresheners that attach to or are inserted into air filters are described in U.S. Pat. No. 3,577,710, Air-Treatment Apparatus, by Feldman (May 4, 1971); U.S. Pat. No. 3,902,877, Container for Air Treating Agent, by Swaim (Jun. 7, 1977); U.S. Pat. No. 4,563,333, Deodorizing Fitting for Air Filters, by Ward (Jan. 5, 1986); and Japanese Patent JPO 04151438, Method and Apparatus for Generating Perfume, by Toshio (May 25, 1992). None of the aforementioned inventions are intended for use in the passenger compartment of an automobile.
Air fresheners that are intended for use in the passenger compartment of an automobile and attachable to the air vents are described in U.S. Pat. No. 5,269,723, Vehicle Air Freshener, by Bender (Dec. 14, 1993); U.S. Pat. No. 5,865,372, Air Freshener for Vehicle, by Ceresko (Feb. 2, 1999); U.S. Pat. No. 6,103,201, Propellar Air Freshener, by Green (Aug. 15, 2000); U.S. Pat. No. 6,123,906, Air Freshening Device for Automobiles, by Blount (Mar. 6, 2001); and U.S. Pat. No. 6,416,043, Louver Air Freshener, by Eisenbaum (Jul. 9, 2002). While the aforementioned devices are suitable for use in an automobile, they do not have a rate controlling mechanism and are only mountable on the vent louvers of the automobile air system.
Air fresheners that are intended for use in the passenger compartment of an automobile, possessing a features to provide limited control over the rate of release of the fragrance, are described in U.S. Pat. No. 4,686,353, Aroma-Generating Automobile Cigarette Lighter, by Spector (Aug. 11, 1987); U.S. Pat. No. 5,373,581, Automobile Plug-In Air Freshener With Rotatable Switch And Vaporizer, by Smith (Dec. 13, 1994); U.S. Pat. No. 5,394,506, Fragrance Dispenser For An Automobile, by Stein (Feb. 28, 1995); U.S. Pat. No. 5,788,931, Air Freshener For Motor Vehicles, by Quintana (Aug. 4, 1998); U.S. Pat. No. 6,021,254, Timed Electric Vehicular Air Freshener, by Hunter (Feb. 1, 2000); and U.S. Patent Application 2002/0176704, Air Freshener For Motor Vehicles, by Roe (Nov. 28, 2002). All of the aforementioned inventions utilize automobile DC socket cigarette lighter to heat a substrate and release a fragrance. U.S. Pat. No. 6,021,254 adds a timer that allows the invention to release fragrance at timed intervals. U.S. Patent Application 2002/176704 allows the user to modify the rate of release by varying the current supplied to a light bulb acting as the heating element for the device. All of the above inventions require active rate control measures on behalf of the user and still provide insufficient control over the release of a fragrance to avoid a fragrance spike early in the life cycle of the fragrance containing substrate. Additionally, the all of the devices occupy a DC socket, a useful automobile appliance, and detract from the aesthetics of the automobile interior.
These prior methods, while useful, fall short of meeting consumer expectations. The most significant problem is the inability of prior devices to regulate the release of the fragrance to achieve a constant release rate. While there have been devices which have made gains in this area through the use of reservoirs surrounded by a rate controlling membrane, none have been entirely successful. Additionally, the duration of such devices is extremely limited, requiring frequent replacement. U.S. Pat. No. 4,874,129 by DiSapio et al. utilizes a multi-layer multi-laminate silicone based device to achieve it's goal of regulating the release of the fragrance. The '129 patent, unlike the present invention, requires layers comprised of adhesives to bind additional layers to the reservoir, uses silicone based oligomers, does not use an additional layer similar to the reservoir to diffuse the fragrance/solvent mix into before release and does not mention doping such a layer to facilitate diffusion, does not modify the cross-link density in order to modify the release rate, and the photo-cure polymer cannot be cured to produce an adhesive cure at desired areas on the surface.
In the published unexamined Japanese Patent Application No. 2000086781 by Takashi et al., the patentee describes photopolymerizing a resin of urethane acrylate oligomer, single organic-function (meta) acrylate, polyfunctional (meta) acrylate, a perfume component, and a photopolymerization initiator to achieve a film which stores perfume. However, the invention described in the Takashi application utilizes urethane acrylates modified to create flexible linkages and blended with other monomers. The present invention does not require modified urethane acrylates and is not blended with other monomers. The present invention utilizes a polybutadiene backbone not described in the Takashi application.
The Takashi device also requires low cross-link densities and low viscosities in order to apply the resin as a coating on sheets while the UV curable, oligomeric composition of the present invention has a significantly higher viscosity. The significantly higher viscosity and cross-link density of the present invention also produces a device which resists shrinkage and cracking thus increasing the useful life of the product by delaying the degradation of the device.